Lock



FIG. 1 is a perspective view of a lock showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines environmental is for illustrative purpose only. The broken line adjacent to the shade lines form the boundary of the claimed design. None of the broken lines form part of the claimed design. 

The ornamental design for a lock, as shown and described. 